Replacement boiler - keep traditional or change to combi?

[jicms]

Hi
Our 30-odd year old Potterton Netaheat boiler has stopped working (fan works but it's not firing).
I've decided not to bother throwing good money after bad and paying someone to come and look at it having cancelled British Gas Homecare some years ago.
I've done some research and it seems Atag or Veissmann are well-made with less plastic parts.
I've received a few online quotes of around £2700 to replace with either the same traditional boiler but also the option to change to a combi for a similar price, including removing the tanks etc. I presumed our 4 bed, 2 bath property couldn't cope with a combi system but the operative said it would and the boiler would be the same 35kw size.
Could anyone confirm this? Also I'm slightly wary of using a fitter of their choosing even though they say their work is fully guaranteed.

 

[JohnD]

If you have two bathrooms, which may sometimes be in use at the same time, a combi is not ideal.

Also, I have a feeling that although your old boiler has stopped working, you can still wash up and have hot baths and showers, because you can heat the cylinder with your immersion heater. Am I right?

A combi breakdown would be more of a calamity.

You have the option of fitting a larger, modern cylinder with a faster reheat if you wish, or an unvented cylinder if you have good incoming flow from the watermain.

 

[DTom]

I cannot advise on your system but if like me your boiler is a long way from where the gas pipe enters your house you may need (like me) to have the whole pipe replaced as mine was not big enough diameter to supply enough gas to the new combi, if i had known this before they started i would have replaced the boiler.

 

[jicms]

That's what I thought but even the Atag boiler finder where you enter all your details says it is. OH doesn't like the idea of changing over even though it will free up a bit of space.

 

[jicms]

I cannot advise on your system but if like me your boiler is a long way from where the gas pipe enters your house you may need (like me) to have the whole pipe replaced as mine was not big enough diameter to supply enough gas to the new combi, if i had known this before they started i would have replaced the boiler.

The boiler is in the kitchen at the back of the house so maybe best to stick with traditional.

 

[DTom]

The boiler is in the kitchen at the back of the house so maybe best to stick with traditional.

My gas pipe enters the house at the front and the boiler is in the garage at the back this is a terraced house so the pipe went under the floor to the boiler two of the floor are concrete so you can imagine the mess.

 

[jicms]

 

[JohnD]

That's what I thought but even the Atag boiler finder where you enter all your details says it is. OH doesn't like the idea of changing over even though it will free up a bit of space.

How many litres per minute of hot water can that boiler provide in summer? (it will be less, or cooler, in winter)

Fill a bucket at your existing bathtap, time it, calculate litres per minute from your cylinder. It may be informative.

 

[jicms]

I would if I was sufficiently keen to changeover. However I think it's easier to keep to traditional as partner won't be happy if I push for a combi it and it goes horribly wrong!!

 

[jicms]

What about using the online boiler comparison sites. Has anyone had a bad experience with their fitters?

If I go with a local tradesman should I purchase the boiler myself or ask for an all-in quote?

 

[JohnD]

If you look at the boiler manufacturers websites, you may find they have a list of local approved installers.

Don't buy the boiler yourself.

 

[flameport]

4 bed, 2 bath property couldn't cope with a combi system but the operative said it would and the boiler would be the same 35kw size

A 35kW combi would be a fairly typical size, the max rating being for the hot water.

A 35kW heat only or system boiler would be grossly oversized for most normal decently insulated properties.

 

[jicms]

Boilercentral recommend this boiler based on my input.
Viessmann 100-W 35kW Regular Open Vent

 

[Gasguru]

There's no such thing as an approved installer...to get on the list by turning up for a days sales pitch at the manufacturer (always remember that manufacturers incentivise installers to push their brand).
Steer clear of Viessman (and Atag)...they are extremely niche manufacturers with 1% market share if they're lucky.
You'll struggle to find anyone willing to look at them when they go wrong and parts are not routinely stocked by merchants.

 

[JohnD]

Boilercentral recommend this boiler based on my input.
Viessmann 100-W 35kW Regular Open Vent

I have the 24kW version, and a well-insulated 3 storey house with HW cylinder. The 35kW model has a bigger case so may not fit in a standard kitchen wall cabinet.
My calculated heat loss at 20C difference is 12.5kW but it used to be left empty during the week and reheated fast on Friday evenings, so oversized rads.

Either your house is enormous, or there is a mistake. I previously had that size in a 5-bedroom detached house. Maybe boilercentral have a lot in stock and want to shift them.

What model is your old Netaheat? Was it sufficient?